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. 2023 Jun 15;127(23):4949-4956.
doi: 10.1021/acs.jpca.3c01857. Epub 2023 May 31.

Reassessing the Composition of Hybrid Orbitals in Contemporary VB Calculations

David L Cooper  1 , Fabio E Penotti  2 , Peter B Karadakov  3
Affiliations

Reassessing the Composition of Hybrid Orbitals in Contemporary VB Calculations

David L Cooper et al. J Phys Chem A. .

Abstract

Large variations in the ratios between the p and s components of individual hybrid orbitals that have been observed in contemporary ab initio VB calculations are reassessed, and links are established to specific energy terms that drive bond formation. It is demonstrated that the ratios between the p and s components for individual hybrid orbitals are not indicative of the overall hybridization status of the relevant atom, which exhibits only relatively small variations with the level of theory, irrespective of whether or not non-dynamical and dynamical electron correlation effects are accounted for. An alternative orbital representation that turns out to be far more consistent with the overall hybridization of the relevant atom is examined. The chosen test cases, which can be compared with the classical sp3, sp2, and sp hybridization models for a central carbon atom, are CH4 (Td), trigonal CH3 (D3h), and triplet CH2 distorted from its ground state geometry so as to be linear (D∞h).

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
Depictions of symmetry-unique SCGVB orbitals for CH4 (top row), CH3 (middle row), and linear triplet CH2 (bottom row).
Figure 2
Figure 2
Depictions of symmetry-unique SCGVB valence LNOs for CH4 (top row), CH3 (middle row) and linear triplet CH2 (bottom row). Also shown are the corresponding occupation numbers, νiLNO. The LNOs have been numbered in each case in order of decreasing νiLNO.
See this image and copyright information in PMC

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